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Some time back I ordered an INA125P Instrumentation Amplifier in order to fool around with a cheap, broken "postal" scale that I had. It arrived and I promptly put it away and forgot it about it. So the other day I was digging through my junk box, saw the scale, and decided to tear it apart. Since it is getting near Halloween, and I knew my grandchildren would be interested, I wrote a little sketch in Energia to estimate the amount of candy in a bowl.
Here is a schematic of the circuit. It "works" but given my skills it may not be best.
This being a MSP430 project I hooked up the sleep pin on the INA125P. I also made it where I could change out Rg, the gain controlling resistor, easily. Once I had it working I made up a little BoosterPack that goes on the bottom of the LaunchPad.
The INA125P sits between the daughter board and the MSP430F5529 LaunchPad - you are looking down on the male pins in the photo above. I hot glued a piece of cardboard on the bottom so as to reduce the chance of shorts and provide a reminder on how to connect it. Below is a view from the bottom with it connected up to the LaunchPad and the scale.
The sketch is here on github. There is a little calibration routine it goes through when started up where it asks for the empty bowl and then a known quantity of candy to be placed into it. After that, it displays on a SHARP96 BoosterPack.
I thought about connecting it up to the IOT, but after due consideration decided I didn't want the neighborhood kids knowing how much candy I have left.